The construction work on the Thane-Borivali underground twin tunnel, passing beneath the Sanjay Gandhi National Park (SGNP), is set to commence in the coming months.
The project’s package 2 is expected to excavate around 3.5 million cubic metres of soil, which equates to the capacity of approximately 1,40,000 large trucks. For this, trucks with a capacity of 25 cubic metres each would be required. Transporting just the 30,000 cubic metres would take 1,200 trucks.
Three potential dumping sites have been proposed for the soil disposal.
An MMRDA official involved in the project said that the contractor Megha Engineering and Infrastructure Ltd has identified three alternative dumping sites near Mankoli, Kalher, and Ranjnoli for this material.
Initially, 30,000 cubic metres of soil will be used for developing the casting yard at Kasarvadavali. However, as per the rules, all necessary permissions will be obtained from regulatory authorities before soil disposal.
For the unversed, the tunnel project is divided into three packages. Package 1 will feature a 5.75-km tunnel on the Borivali side, Package 2 will see a 6.05-km tunnel on the Thane side and Package 3 will cover the procurement and installation of electrical, mechanical and fire systems, along with ventilation.
Features of twin-tunnel:
As per reports, the total length of the tunnel is 11.8 km, with an outer diameter of 13.05 metres (two lanes per tunnel plus one emergency lane), and cross passages every 300 metres.
The twin tunnels will pass beneath the Sanjay Gandhi National Park, connecting Tikuji-Ni-Wadi in Thane to the Western Express Highway in Borivali.
This tunnel will reduce travel distance by 12 km and save motorists about one hour, offering significant reductions in time and fuel costs. The project’s cost is estimated at Rs 14,400 crore. It is expected to ease congestion on Ghodbunder Road by providing a quicker alternative route between Thane and Borivali.
The Mumbai Metropolitan Region Development Authority (MMRDA) will use a Tunnel Boring Machine (TBM) to minimise disruption to the park’s biodiversity. The entire project is expected to take over 5 years to complete.The tunnel will allow vehicles to travel at a top speed of 80 km/h, reducing travel time by 40 to 45 minutes and saving an estimated 10.5 lakh metric tonnes of fuel. It will also contribute to a 36 per cent reduction in carbon dioxide emissions. Measures such as cross tunnels, smoke detection systems, and jet fans to ensure clean and fresh air within the tunnel.